1. Field of the Invention
Exemplary embodiments of the present invention relate to a method and apparatus for transmitting/receiving a multi-view program including a stereoscopic 3D program in a digital broadcasting system; and, more particularly, to a method and apparatus for transmitting/receiving a multi-view program composed of a plurality of video streams through a plurality of physical channels while maintaining service compatibility with a conventional 2D receiver.
2. Description of Related Art
In digital broadcasting systems, channels do not means physical radio frequency (RF) channels but mean virtual channels.
Conventional digital broadcasting systems have a structure in which data is transmitted through one or more logical virtual channels within one physical RF channel. For example, in a conventional two-dimensional (2D) digital broadcasting system, a program has one video stream, and the video stream is generally transmitted through virtual channels within one physical RF channel.
Meanwhile, since a stereoscopic 3D image expresses a 3D effect using a difference in visual angle between a left-view image (hereinafter, referred to as a ‘left image’) and a right-view image (hereinafter, referred to as a ‘right image’), a stereoscopic 3D program has video streams for the left and right images to be transmitted. There are several methods for transmitting a video stream composed of left and right images. For example, a first method, as illustrated in FIG. 1A, is a method of decreasing the resolution of left and right images by a half with respect to width, combining the left and right images together as one image frame and then compressing the image frame, thereby transmitting the compressed image frame as one video stream. A second method is a method of decreasing the resolution of left and right images by a half with respect to length, combining the left and right images together as one image frame and then compressing the image frame, thereby transmitting the compressed image frame as one video stream. A third method, as illustrated in FIG. 1B, is a method of compressing left and right images for each frame and then transmitting the compressed left and right images as two video streams. For reference, in FIGS. 1A and 1B, “L” denotes a left image and “R” denotes a right image. In the first and second methods, an image having a resolution decreased by a half is transmitted, and therefore, deterioration of image quality occurs. However, in the third method, 3D watching is possible without deterioration of image quality. When comparing these methods in terms of transmission, the first and second methods have no difference from the conventional method of transmitting the 2D program. However, in the third method, two video streams are transmitted, and therefore, the quantity of data to be transmitted may exceed the capacity of one physical RF channel. In this case, there occurs a problem in that the two video streams are transmitted through one physical RF channel, like the conventional method of transmitting the 2D program.
If the method of transmitting video streams is not limited to a stereoscopic 3D program having two video streams to be transmitted but extended to a multi-view program having several video streams to be transmitted, it is almost impossible to transmit the multi-view program through one physical RF channel.
As described above, there is a limitation in transmitting a multi-view program including a stereoscopic 3D program through one physical RF channel, and therefore, the multi-view program is necessarily transmitted through two or more physical RF channels.
Since the capacity of the virtual channel through which the 2D program is transmitted does not exceed the capacity of the one physical RF channel, it is not generally considered in signaling information for receiving the conventional 2D program that a plurality of physical RF channels are received, and video streams transmitted through the respective physical channels are linked. Therefore, signaling information for receiving a virtual channel through which a multi-view program including a stereoscopic 3D program transmitted within a plurality of physical RF channels is necessarily contained in the signaling information for receiving the conventional 2D program.
Although the quantity of data of the 3D program having two video streams does not exceed the capacity of the one physical RF channel, the signaling information for receiving the virtual channel through which the multi-view program including the stereoscopic 3D program transmitted within the plurality of physical RF channels is necessarily provided even when watching the stereoscopic 3D program by transmitting a video stream corresponding to the right image through a separate physical RF channel, transmitting a video stream corresponding to the left image through the conventional 2D program channel and then liking video streams transmitted from a receiving stage to each of the channels so that the configuration of channels built to transmit the conventional 2D program is not changed.